Entry number “consists of a three-position entry filer code and a seven-position transaction code, plus a check digit assigned by the entry filer as a tracking number for goods entered into the U.S.” [15 CFR 30.1; Title 15 -- Commerce And Foreign Trade; Subtitle B -- Regulations Relating To Commerce And Foreign Trade; Chapter I -- Bureau Of The Census, Department Of Commerce; Part 30 -- Foreign Trade Regulations; Subpart A -- General Requirements]